EP1223185B1 - Polyamide and process for its preparation - Google Patents

Abstract

Polyamide contains molecular chains of formula (I) or (II): R1-Ä-A-X-(-Y-R2-Z)n-R3Üm (I) R4-Ä-Y-R2-Z-Üp-R3 (II) Y = -N(R5)- when X and Z = -C(O)-; and Y = -C(O)- when X and Z = -N(R5)-; A = a covalent bond or a 1-20 C aliphatic hydrocarbon radical which may contain heteroatoms; R2 = 2-20 C optionally branched aliphatic or aromatic group; R3, R4 = H or a hydrocarbon group containing a -C(O)- or -N(R5)- group; R5 = H or 1-6 C hydrocarbon group; R1 = a linear or cyclic, aromatic or aliphatic hydrocarbon group with at least 2C and optionally containing heteroatoms; m = 3-8; n =100-200; and p = 100-200. Also claimed is a process for the production of a polyamide.

Description

The present invention relates to a polyamide comprising macromolecular chains of different chemical structure, and a method of manufacture thereof as well as compositions containing it.

It relates more particularly to a polyamide consisting of polymer units having a star configuration and linear polymer units.

The use of linear aliphatic or semi-aromatic polyamides as a plastic material forming the matrix of a composition intended to be shaped has been known for a very long time. To improve the mechanical properties of these plastics, these compositions comprise fillers in the form of powder or fibers, such as, for example, glass fibers. However, these fillers cause an increase in the viscosity of the melt composition, or more generally limit the flow rate of the composition when it is injected into a mold. To obtain a correct filling of the molds or a fast molding rate, it is necessary to limit the amount of filler in the composition. Thus, the maximum permissible concentrations are generally close to 40% by weight.

This slow or difficult flow of loaded or unloaded compositions also results in a poor surface appearance of the molded parts. Indeed, charges such as fibers are visible on the surface of the room. To remedy this problem, it has been proposed to add an amorphous polymer or having a slower crystallization kinetics to the semi-crystalline matrix, especially when the latter is a hexamethylene polyadipamide.

It has also been proposed to use low molecular weight polymers to thereby improve mold filling, as for example in US Pat. No. 5,274,033. However, the mechanical properties of the material are diminished.

Polyamides having a star structure obtained with aromatic polyfunctional compounds are described in US Pat. No. 5,346,984. However, these polymers exhibit a completely star-shaped structure and have low molecular weights. These two characteristics limit their use for the manufacture of molded parts or in industrial and technical applications because their mechanical properties are insufficient.

One of the aims of the present invention is to remedy these drawbacks by proposing a polyamide having a high melt flow fluidity and comparable or improved mechanical properties compared to a conventional linear polyamide. This polyamide can be used as an element or component of a polyamide. a polymer matrix in a composition containing a high charge rate. Such a composition has good injectability for the manufacture of moldings.

dans lesquelles :

• Y est le radical
  
  quand X et Z représentent le radical
  
• Y est le radical
  
  quand X et Z représentent le radical
  
• A est une liaison covalente ou un radical hydrocarboné aliphatique pouvant comprendre des hétéroatomes, et comprenant de 1 à 20 atomes de carbone, de préférence de 1 à 6 atomes de carbone.
• R₂ est un radical hydrocarboné aliphatique ou aromatique ramifié ou non comprenant de 2 à 20 atomes de carbone.
• R₃ représente :
  • l'hydrogène lorsque Z représente le radical
    
    ;
  • l'hydroxyle lorsque Z représente le radical
    
    ; ou
  • un radical hydrocarboné comprenant un groupement :
    
  ou
  
• R₄ représente :
  • l'hydrogène lorsque Y représente le radical
    
  • l'hydroxyle lorsque Y représente le radical
    
    ou
  • un radical hydrocarboné comprenant un groupement :
    
  ou
  

For this purpose, the invention provides a polyamide consisting of a mixture of macromolecular chains of formulas I and II as follows:

in which :

• Y is the radical
  
  when X and Z represent the radical
  
• Y is the radical
  
  when X and Z represent the radical
  
• A is a covalent bond or an aliphatic hydrocarbon radical which may include heteroatoms, and comprising 1 to 20 carbon atoms, preferably 1 to 6 carbon atoms.
• R ₂ is a branched or unbranched aliphatic or aromatic hydrocarbon radical containing from 2 to 20 carbon atoms.
• R ₃ represents:
  • hydrogen when Z represents the radical
    
    ;
  • hydroxyl when Z represents the radical
    
    ; or
  • a hydrocarbon radical comprising a grouping:
    
  or
  
• R ₄ represents:
  • hydrogen when Y represents the radical
    
  • hydroxyl when Y represents the radical
    
    or
  • a hydrocarbon radical comprising a grouping:
    
  or
  

• R₁ est un radical hydrocarboné comprenant au moins 2 atomes de carbone, linéaire ou cyclique, aromatique ou aliphatique et pouvant comprendre des hétéroatomes.
• m est un nombre entier compris entre 3 et 8 (bornes incluses)
• n est un nombre compris entre 100 et 200 (bornes incluses)
• p est un nombre compris entre 100 et 200 (bornes incluses)

caractérisé en ce que le rapport massique entre le poids de chaînes polymères de formule I et le poids total de chaînes polymères de formules I et II est compris entre 0,6 et 0,9.R ₅ represents hydrogen or a hydrocarbon radical comprising from 1 to 6 carbon atoms

• R ₁ is a hydrocarbon radical comprising at least 2 carbon atoms, linear or cyclic, aromatic or aliphatic and may comprise heteroatoms.
• m is an integer between 3 and 8 (limits included)
• n is a number between 100 and 200 (limits included)
• p is a number between 100 and 200 (limits included)

characterized in that the mass ratio between the weight of polymer chains of formula I and the total weight of polymer chains of formulas I and II is between 0.6 and 0.9.

According to a preferred characteristic of the invention, the radical R ₂ is a pentamethylene radical. In this embodiment, the polyamide has a polycaproamide or PA 6 type structure.

However, other radicals R ₂ can be used, such as the undecamethylenic radicals, which leads to a polyamide with structure type PA 12. It is also possible to obtain polyamides having R ₂ radicals comprising 8 or 10 corresponding carbon atoms respectively polyamides of structure type PA9 and PA11.

More generally, radicals R ₂ which are amino acid or lactam residues are suitable for the present invention.

According to yet another preferred feature of the invention, the radical R ₁ is either a cycloaliphatic radical such as the tetravalent cyclohexanonyl radical, or a 1,1,1-triylpropane, 1,2,3-triylpropane radical. triyl.

Other radicals R ₁ suitable for the invention include, for example, the trivalent radicals of phenyl and cyclohexanyl, which may or may not be substituted, the tetravalent diaminopolymethylene radicals with a number of methylene groups advantageously between 2 and 12 such that the radical derived from EDTA (ethylene diamino tetraacetic acid), the octovalent radicals of cyclohexanonyl or cyclohexadinonyl, and the radicals derived from compounds derived from the reaction of polyols such as glycol, pentaerythritol, sorbitol or mannitol with acrylonitrile.

The radical A is preferably a methylene or polymethylene radical such as ethyl, propyl or butyl radicals, or a polyoxyalkylene radical such as the polyoxyethylene radical.

According to a preferred embodiment of the invention, the number m is equal to 3 or 4.

Thus, the polymeric chains of formula I define a star polyamide comprising polyamide branches of PA 6 type in one of the preferred embodiments of the invention, and a central core consisting of a cycloaliphatic nucleus.

avantageusement supérieur à 10 000.The length or the molecular weight of the linear chains of formula II or branches of star polyamide can be high. Thus, the linear polymer as the chain of each branch of the star polymer presents a $\widetilde{\mathrm{M}\mathrm{not}}$

advantageously greater than 10,000.

en présence d'un composé polyfonctionnel de formule V : R₁[A-X-H] lorsque X représente le radical-

; et

• R₁[A-X-OH]_m lorsque X représente le radical
  

dans lesquelles les symboles R₁, R₂, A, X et m ont les significations indiquées précédemment,
en présence d'un initiateur de polycondensation.The invention also relates to a method of manufacturing the polyamide described above. This manufacturing process consists in carrying out a polycondensation of an amino acid or a lactam of formulas III and IV as follows:

HOOC-R ₂ -NH ₂ (III)

in the presence of a polyfunctional compound of formula V: R ₁ [AXH] when X represents the radical-

; and

• R ₁ [AX-OH] _m when X represents the radical
  

in which the symbols R ₁ , R ₂ , A, X and m have the meanings indicated above,
in the presence of a polycondensation initiator.

The reactive function of the multifunctional compound represented by the symbol X-H is a function capable of forming an amide function.

ou les composés provenant de la réaction du triméthylol propane ou du glycérol avec l'oxyde de propylène et amination des groupes hydroxydes terminaux, ces derniers composés sont commercialisés sous le nom commercial JEFFAMINES T® par la société HUNTSMAN, et ont comme formule générale :

Dans laquelle :

• R₁ représente un radical 1,1,1-triyle propane, ou 1,2,3-triyle propane,
• A représente un radical polyoxyéthylénique.

les initiateurs de polycondensation sont ceux classiquement utilisés dans la synthèse des polyamides par polycondensation d'un lactame ou d'un aminoacide, tel que la synthèse du polycaproamide.By way of example of polyfunctional compounds of formula V, mention may be made of the compound 2,2,6,6-tetra- (β-carboxyethyl) cyclohexanone, the compound diaminopropane-N, N, N ', N' tetraacetic acid of following formula:

or the compounds resulting from the reaction of trimethylolpropane or glycerol with propylene oxide and amination of the terminal hydroxide groups, these latter compounds are marketed under the trade name JEFFAMINES T® by the company Huntsman, and have the general formula:

In which :

• R ₁ represents a 1,1,1-triylpropane or 1,2,3-triylpropane radical,
• A represents a polyoxyethylene radical.

the polycondensation initiators are those conventionally used in the synthesis of polyamides by polycondensation of a lactam or of an amino acid, such as the synthesis of polycaproamide.

By way of example, mention may be made of water, mineral or carboxylic acids or primary amines as a polycondensation initiator.

This compound is advantageously added to obtain a weight concentration of between 0.5 and 5% by weight relative to the total mixture.

The polycondensation is carried out according to the conventional polycondensation operating conditions of the amino acids or lactams of formula III or IV, when this is carried out in the absence of the multifunctional compound of formula V.

• un chauffage sous agitation et sous pression du mélange des monomères (composés de formule III et/ou IV) et du composé de formule V avec l'initiateur (généralement de l'eau),
• Maintien du mélange à cette température pendant une durée déterminée, puis décompression et maintien sous un courant de gaz inerte (par exemple de l'azote) pendant une durée déterminée à une température supérieure au point de fusion du mélange pour ainsi continuer la polycondensation par élimination de l'eau formée.

Thus, the polycondensation process briefly comprises:

• heating under stirring and under pressure the mixture of the monomers (compounds of formula III and / or IV) and of the compound of formula V with the initiator (generally water),
• Maintaining the mixture at this temperature for a predetermined period, then decompressing and maintaining under a stream of inert gas (eg nitrogen) for a specified time at a temperature above the melting point of the mixture to thereby continue the polycondensation by elimination water formed.

According to the process of the invention, the duration of the maintenance under inert gas, or in other words of finishing of the polycondensation makes it possible to determine and control the concentration of polymer chains of formula I in the polyamide mixture. Thus, the longer the holding time, the higher the concentration of polymer chains of formula I will be.

It is also evident that the concentration of polymer chains of formula I or star polyamide is a function of the amount of multifunctional compound of formula V added to the mixture.

It is also possible, without departing from the scope of the invention, to add to the polycondensation mixture other monomers comprising functions capable of forming amide functions to thereby obtain modified copolyamides or polyamides.

However, when these monomers are diacids or diamines, they can be added in small quantities advantageously at a concentration by weight of less than 20% relative to the total mixture.

At the polycondensation outlet, the polymer is advantageously cooled by water and extruded in the form of a rod. These rushes are cut to produce pellets.

To remove non-polycondensed monomers, especially in the case where one of the monomers is caprolactam, the granules are washed with water and then dried under vacuum.

The polymer obtained can be shaped according to the usual techniques of molding, extrusion, spinning to produce molded parts, films, wires.

Advantageously, the polyamide of the invention is used as element or component of a thermoplastic matrix of a composition intended to be shaped for the manufacture of molded parts.

The composition comprises a polymer matrix, advantageously thermoplastic material and fillers modifying the properties of the matrix such as its mechanical properties, fireproofing, thermal conductivity, electrical or magnetic, or the like. Examples of usual fillers include reinforcing fillers or fillers.

The polymer matrix comprises as a single component or not the polyamide according to the invention.

Since the polyamide according to the invention has a higher melt flow index than the known linear polyamides, for similar molecular weights and mechanical properties, the charged composition can be more easily injected into a mold. that is, at higher rates. It also makes it possible to obtain a more homogeneous and complete filling of the molds, especially when they have a complex shape.

The polyamide of the invention also makes it possible to produce compositions containing a high level of charge which may be up to 80% by weight relative to the total composition.

Such a composition can be injected thanks to the high melt flow index of the polyamide of the invention. The mechanical properties of this composition are high because they are generally improved when the charge rate increases.

Suitable filler or reinforcing fillers for the invention are the fillers usually used to reinforce the polymer material compositions, such as fibrous fillers comprising mineral fibers such as, for example, glass fibers, fibers carbon fibers, ceramic fibers, synthetic fibers such as polyaramid fibers, powder fillers such as talc, montmorillonite, kaolin for example.

Powder fillers are also used to improve the flame retardancy of the composition. Such fillers are, for example, metal compounds such as magnesium hydroxide or aluminum hydroxide.

Glass fibers are the preferred reinforcing filler of the invention.

According to another preferred characteristic of the invention, the polymer matrix of the composition consists of a mixture of the polyamide according to the invention with one or more other polymers, preferably polyamides or copolyamides.

Other preferred polymers of the invention include semicrystalline or amorphous polyamides, such as aliphatic polyamides, semi-aromatic polyamides and, more generally, linear polyamides obtained by polycondensation between an aliphatic or aromatic saturated diacid and a primary diamine saturated aromatic or aliphatic, a lactam, an amino acid or a mixture of these different monomers.

By way of example, mention may be made, as other polymers, of hexamethylene polyadipamide, polyphthalamides obtained from terephthalic and / or isophthalic acid, such as the polyamide marketed under the trade name AMODEL, and copolyamides obtained from acid. adipic acid, hexamethylene diamine and caprolactam.

In this embodiment, the weight concentration of polyamide according to the invention in the matrix may vary over a wide range and is advantageously between 30 and 80% of the total mass of the polymer matrix.

It is also advantageous, especially in this case, that the mass ratio of star polyamide (formula I) in the polyamide of the invention is greater than 0.8.

The compositions of the invention may also include all the usual additives such as flame retardants, heat and light stabilizers, waxes, pigments.

Such compositions are used to produce moldings for the automotive industry, electrical components, accessories for various activities such as sports activities, for example.

Other details and advantages of the invention will emerge more clearly from the examples given below solely for illustrative and illustrative purposes.

Example 1 - Synthesis of a polyamide according to the invention

The polymerization is carried out in a heated autoclave and comprising stirring means.

4444 g of caprolactam and 136 g of 2,2,6,6-tetra- (β-carboxyethyl) cyclohexanone are added to the autoclave with 160 g of distilled water.

The cyclohexanone compound and its method of synthesis are described in the article "The Chemistry of Acrylonitrile II - Reactions with Ketones" JACS 64 2850 (1942) by Herman Alexander Buison and Thomas W. Riener.

The mixture, stirred, is heated to a temperature of 265 ° C under 6 bar.

It is maintained at this temperature and pressure for 2 hours.

The pressure is then decreased, then a nitrogen autoclave is swept for varying periods of time while maintaining the temperature at 265 ° C.

The star polymer concentration of formula I is determined for each scan time.

This concentration is determined by the method developed by FARINA et al. and described in the report of the 4th Italian Convention on the Science of the Macromolecule.

In summary, this method consists in calculating the weight ratio of star polymer in the mixture by determining the concentration of amine and / or acid end groups and calculating the polymolecularity index D which is equal to $\frac{\widetilde{\mathrm{M}\mathrm{w}}}{\widetilde{\mathrm{M}\mathrm{not}}}.$

dans laquelle :

• X_W1 représente la fraction en poids du polymère de poids moléculaire en nombre ${\overline{\mathrm{M}\mathrm{n}}}_1$
  
  et d'indice de polymolécularité D₁.

Cette équation convient également très bien pour les composés polymériques contenant un composant multifonctionnel. En fait, si on a un mélange de polymère linéaire de fonctionnalité (f) égale à 2 et de polymère étoile de fonctionnalité (f) supérieure à 2 on peut faire les hypothèses suivantes :

• le mélange est composé uniquement de chaînes totalement linéaires et de chaînes totalement de type étoile.
• la longueur des chaînes linéaires est égale à celle d'une branche du polymère étoile.

Selon ces hypothèses, l'équation (1) a été transformée par M. FARINA en une équation (2) suivante : $$\mathrm{D}=2-\frac{{\left(\mathrm{f}-1\right)}^2}{\mathrm{f}}{\mathrm{X}}_{\mathrm{W}2}^2+\frac{\left(\mathrm{f}-1\right)\left(\mathrm{f}-2\right)}{\mathrm{f}}{\mathrm{X}}_{\mathrm{W}2}$$

avec: $$\overline{\mathrm{M}\mathrm{n}2}=\mathrm{f}\cdot \overline{\mathrm{M}\mathrm{n}1},\mathrm{\hspace{0.17em}}{\mathrm{D}}_1=2,\mathrm{\hspace{0.17em}}\mathrm{D}2=1+\frac{1}{\mathrm{f}}$$

Avec une telle équation il est possible de calculer la relation entre D et la fraction en poids de X_W2 de polymère étoile dans le mélange polymérique. Cette relation est une fonction du coefficient de fonctionnalité (f) du composé multifonctionnel comme représentée dans la figure 1 annexée.Indeed, according to an article by W. SWEENY and J. ZIMERMAN published in "ENCYCLOPEDIA OF POLYMER SCIENCE AND TECHNOLOGY Vol.10 pp194, the classical equation of calculation of the index D for a polymer mixture is: $$\mathrm{D}=\frac{\widetilde{\mathrm{M}\mathrm{w}}}{\widetilde{\mathrm{M}\mathrm{not}}}={\mathrm{X}}_{\mathrm{W}1}^{\mathrm{two}}{\mathrm{D}}_1+{\mathrm{X}}_{\mathrm{W}1}^{\mathrm{two}}{\mathrm{D}}_{\mathrm{two}}+{\mathrm{X}}_{\mathrm{W}1}{\mathrm{X}}_{\mathrm{W}\mathrm{two}}\left[{\mathrm{D}}_1\frac{{\widetilde{\mathrm{M}\mathrm{not}}}_1}{{\widetilde{\mathrm{M}\mathrm{not}}}_{\mathrm{two}}}+{\mathrm{D}}_{\mathrm{two}}\frac{{\widetilde{\mathrm{M}\mathrm{not}}}_{\mathrm{two}}}{{\widetilde{\mathrm{M}\mathrm{not}}}_1}\right]$$

in which :

• X _W1 represents the fraction by weight of the polymer of molecular weight in number ${\widetilde{\mathrm{M}\mathrm{not}}}_1$
  
  and of polymolecularity index D ₁ .

This equation is also very suitable for polymeric compounds containing a multifunctional component. In fact, if we have a linear polymer mixture of functionality (f) equal to 2 and polymer star of functionality (f) greater than 2, we can make the following assumptions:

• the mixture consists only of totally linear chains and totally star-like chains.
• the length of the linear chains is equal to that of a branch of the star polymer.

According to these hypotheses, equation (1) was transformed by M. FARINA into an equation (2): $$\mathrm{D}=\mathrm{two}-\frac{{\left(\mathrm{f}-1\right)}^{\mathrm{two}}}{\mathrm{f}}{\mathrm{X}}_{\mathrm{W}\mathrm{two}}^{\mathrm{two}}+\frac{\left(\mathrm{f}-1\right)\left(\mathrm{f}-\mathrm{two}\right)}{\mathrm{f}}{\mathrm{X}}_{\mathrm{W}\mathrm{two}}$$

with: $$\widetilde{\mathrm{M}\mathrm{not}\mathrm{two}}=\mathrm{f}\cdot \widetilde{\mathrm{M}\mathrm{not}1},\mathrm{}{\mathrm{D}}_1=\mathrm{two},\mathrm{}\mathrm{D}\mathrm{two}=1+\frac{1}{\mathrm{f}}$$

With such an equation it is possible to calculate the relationship between D and the weight fraction of X _W2 of star polymer in the polymer blend. This relationship is a function of the function coefficient (f) of the multifunctional compound as shown in the appended FIG.

Ainsi, il est aisé de calculer D et d'autres paramètres importants tels que : $$\begin{array}{l}\overline{{\mathrm{M}}_{\mathrm{n}}}={10}^6/\left[\mathrm{C}\mathrm{o}+\mathrm{N}{\mathrm{H}}_2\right]\\ \overline{{\mathrm{M}}_{\mathrm{w}}}=2\cdot {10}^6\left[10\mathrm{C}\mathrm{o}+\mathrm{N}{\mathrm{H}}_2\right]/{\left[4\mathrm{C}\mathrm{o}+\mathrm{N}{\mathrm{H}}_2\right]}^2\\ {\mathrm{X}}_{\mathrm{w}2}=\left[\mathrm{C}\mathrm{O}\mathrm{O}\mathrm{H}-\mathrm{N}{\mathrm{H}}_2\right]/\left[\mathrm{C}\mathrm{O}\mathrm{O}\mathrm{H}\right]\end{array}$$

Le polymère fondu est ensuite extrudé sous forme de jonc puis refroidi rapidement à l'eau et découpé en granulés.Equation (2) can be transformed by introducing experimental parameters such as the molar concentration Co of the multifunctional compound and the concentration expressed in milliequivalents per kilogram of the terminal functions NH ₂ and COOH: $$\mathrm{D}=\mathrm{two}-\mathrm{f}{\left(\mathrm{f}-1\right)}^{\mathrm{two}}{\left(\frac{\mathrm{VS}\mathrm{o}}{\mathrm{f}\mathrm{VS}\mathrm{o}+\left[\mathrm{NOT}{\mathrm{H}}_{\mathrm{two}}\right]}\right)}^{\mathrm{two}}+\left(\mathrm{f}-1\right)\left(\mathrm{f}-\mathrm{two}\right)\frac{\mathrm{VS}\mathrm{o}}{\mathrm{f}\mathrm{VS}\mathrm{o}+\left[\mathrm{NOT}{\mathrm{H}}_{\mathrm{two}}\right]}$$

Thus, it is easy to calculate D and other important parameters such as: $$\begin{array}{l}\widetilde{{\mathrm{M}}_{\mathrm{not}}}={10}^6/\left[\mathrm{VS}\mathrm{o}+\mathrm{NOT}{\mathrm{H}}_{\mathrm{two}}\right]\\ \widetilde{{\mathrm{M}}_{\mathrm{w}}}=\mathrm{two}\cdot {10}^6\left[10\mathrm{VS}\mathrm{o}+\mathrm{NOT}{\mathrm{H}}_{\mathrm{two}}\right]/{\left[4\mathrm{VS}\mathrm{o}+\mathrm{NOT}{\mathrm{H}}_{\mathrm{two}}\right]}^{\mathrm{two}}\\ {\mathrm{X}}_{\mathrm{w}\mathrm{two}}=\left[\mathrm{VS}\mathrm{O}\mathrm{O}\mathrm{H}-\mathrm{NOT}{\mathrm{H}}_{\mathrm{two}}\right]/\left[\mathrm{VS}\mathrm{O}\mathrm{O}\mathrm{H}\right]\end{array}$$

The molten polymer is then extruded as a rod and then rapidly cooled with water and cut into granules.

These granules are washed with distilled water for about 16 hours to remove unpolymerized caprolactam and dried at 100 ° C under vacuum for 48 hours.

Different polymers have been manufactured with variable star polyamide levels.

A 0,5 % 60 min. 0,60 10343 2,04 B 0,5 % 90 min. 0,70 20630 1,97 C 0,5 % 120 min. 0,90 19400 1,46 D (comparatif) 0,5 % 140 min. 1,00 20900 1,25 E 0,3 % 90 min. 0,70 21152 1,8 F 0,8 % 100 min. 0,70 13661 1,3 ex. comparatif 1 0 90 min. 0,00 19550 2 The production conditions and the characteristics of these polymers are collated in Table I below. <u> Table I </ u> Polymer mol% of tetrafunctional compounds Scan time Mass ratio in star polymer M̅ _n n $\mathrm{D}=\frac{\widetilde{{\mathrm{M}}_{\mathrm{w}}}}{\widetilde{{\mathrm{M}}_{\mathrm{not}}}}$

AT 0,5% 60 min. 0.60 10343 2.04 B 0,5% 90 min. 0.70 20630 1.97 VS 0,5% 120 min. 0.90 19400 1.46 D (comparative) 0,5% 140 min. 1.00 20900 1.25 E 0.3% 90 min. 0.70 21152 1.8 F 0.8% 100 min. 0.70 13661 1.3 ex. comparative 1 0 90 min. 0.00 19550 two

The rheological and mechanical properties of these polymers are summarized in Table II below. <u> Table II </ u> AT B VS D * E F * 1 Relative viscosity (1) 2.07 2.06 2.02 2.15 2.56 1.77 2.7 Melt flow rate (2) (g / 10min) 47 45 44 45 13.5 70.2 7.5 Melting temperature ° C 219 218 217 217 219 217 221 Crystallization temperature ° C 181 179 178 176 179 177 175 Tg ° C 72 74 73 74 74 72 67 Notched Izod Shock (J / m) 45 47 42 40 47.3 32 38.4 Flexural modulus (MPa) 2400 2400 2500 2500 3300 2700 2500 Lengthening% 160 140 100 80 140 70 100 Tensile strength (MPa) 78 78 76 80 78 80 78 (1) Relative Viscosity Measured from a 1% Polymer Solution in 96% H ₂ SO ₄ (2) Flow index (MFI) determined according to ASTM D1238 *comparative

These results clearly show that for equivalent molecular weights, melt flow index increases drastically when the concentration of multifunctional compound reaches about 0.50%.

Example 2 : Loaded Compositions

Compositions comprising a polyamide matrix are filled with glass fibers by melt blending in a twin-screw extruder type WERNER and PFLEIDERER ZSK 40.

Thus compositions containing 50% by weight of glass fibers are made respectively with a conventional PA 6, or a polyamide according to the invention having a weight ratio of star polymer equal to either 0.78 or 0.98.

The production parameters of the mixture and the extrusion are collated in the following Table III: <u> Table III </ u> Matrix PA 6 Polyamide with mass ratio in star polymer equal to 0.78 Polyamide with a mass ratio of polymer star equal to 0.98 (comparative) Extrusion temperature 250 ° C 250 ° C 250 ° C Speed of rotation of the screw (turn per min.) 260 260 260 Composition rate (Kg / h) 40 40 40 engine torque (Nm) 42 28 23 Absorbed motor power expressed in Ampere (A) 34 30 25

The properties of these compositions are shown in Table IV below. <u> Table IV </ u> Matrix PA 6 Polyamide with mass ratio in star polymer equal to 0.78 Polyamide with a mass ratio of polymer star equal to 0.98 (comparative) Module (MPa) 15350 15935 15792 Notched Izod Shock (J / m) 124 139.3 128.3 Not Izod Shock (MPa) 94 96 95 HDT (° C) (1) 215 214 215 Molten viscosity index (g / 10min) 6 12.5 12 Spiral test (cm) (2) 25 50 46 (1) measured according to ASTM D648 under a load of 1.82 N / mm ² (2) This test consists of injecting the composition into a spiral-shaped mold 1 mm thick and 40 mm wide under a 180-ton BATTENFELD press at a temperature of 270 ° C., a mold temperature of 80 ° C. and an injection pressure of 80 kg / cm ² . The injection time is 1.5 seconds. The result of the test is determined by the mold length filled correctly by the composition.

• Température : 250 °C
• Vitesse de rotation de la vis : 260 tours par min.
• Débit de la composition : 40 Kg/h

Similarly, a composition comprising 60% by weight of glass fibers and as matrix a PA6-type polyamide with a weight ratio of star polymer equal to 0.78 is prepared according to the process described above with the following mixing and extrusion conditions:

• Temperature: 250 ° C
• Speed of rotation of the screw: 260 revolutions per min.
• Flow rate of the composition: 40 Kg / h

The properties of this composition are shown in Table V below in comparison with a composition comprising 60% by weight of glass fibers and as matrix a linear PA6 polyamide with identical molecular weight: <u> Table V </ u> Matrix PA 6 with 60% fiberglass Polyamide with mass ratio in star polymer equal to 0.78 Module (MPa) 18556 20251 Notched Izod Shock (J / m) 123 118 Not Izod Shock (MPa) 83 86 HDT (° C) (1) 215 215 Spiral test (cm) (2) 24 35 engine torque (Nm) 43 32 Absorbed motor power expressed in Ampere (A) 35 25

Example 3 Synthesis of a second polymer type according to the invention

• 4444 g de caprolactame
• 54 g de 1,3 diaminopropane - N,N,N',N' acide tétraacétique
• 160 g d'eau distillée

According to a procedure identical to that of Example 1, a polyamide according to the invention is manufactured from a mixture of monomers according to:

• 4444 g of caprolactam
• 54 g of 1,3 diaminopropane - N, N, N ', N' tetraacetic acid
• 160 g of distilled water

The properties of the polymer (G) obtained are collated in Table VI below.

Example 4 Synthesis of a Third Polymeric Type According to the Invention

• 4444 g de caprolactame
• 71 g de JEFFAMINES® 403 commercialisée par la société HUNTSMAN
• 160 g d'eau distillée

According to a procedure identical to that of Example 1, a polyamide according to the invention is manufactured from a mixture of monomers according to:

• 4444 g of caprolactam
• 71 g of JEFFAMINES® 403 marketed by the company HUNTSMAN
• 160 g of distilled water

The properties of the polymer (H) obtained are collated in Table VI below.

A polymer (J) was made with the same compounds of the above example but using 142 g of JEFFAMINES® instead of 71 g. The properties of this polymer are summarized in Table VI.

As a comparative example, a conventional polyamide polymer was made under the same conditions but using as monomers only a mixture containing 4444 g of caprolactam and 160 g of water. The properties of this polymer 2 are shown in Table VI. <u> Table VI </ u> BOY WUT H J two Relative viscosity (1) 2.15 2.05 1.70 2.70 Number of amine endings (meq / Kg) 26 104 190 52 Number of acid terminations (meq / Kg) 115 20 17 50 Melt flow rate (2) (g / 10min) 26 13 35 7.5 Melting temperature ° C 219 218 216 221 Crystallization temperature ° C 174 172 168 175 Notched Izod Shock (J / m) 48 49 44 38.4 Flexural modulus (MPa) 2535 2690 2782 2500 Lengthening% 145 59 42 100 Tensile strength (MPa) 65 73 72 78 (1) Relative Viscosity Measured from a 1% Polymer Solution in 96% H ₂ SO ₄ (2) Flow index (MFI) determined according to ASTM D1238

Example 5 Loaded compositions

Compositions were prepared by extrusion with a WERNER ZSK 40 extruder at a temperature of 250 ° C of a mixture comprising as polymeric matrix a polymer prepared in Examples 3 and 4 and, 50% by weight relative to the mass of the composition total fiberglass.

The properties of these compositions are summarized in Table VII below: <u> Table VII </ u> Matrix Polymer 2 (PA 6) Polymer G Polymer H Polymer J Module (MPa) 15300 15060 15200 15100 Notched Izod Shock (J / m) 124 121 121 123 Tensile strength (N / mm ² ) 220 216 214 211 HDT (° C) (1) 211 210 207 208 Molten viscosity index (g / 10min) 5.2 13.7 9.3 14.4 Spiral test (cm) (2) 21.5 35 43 45 (1) measured according to ASTM D648 under a load of 1.82 N / mm ² (2) This test consists in injecting the composition into a spiral-shaped mold 1 mm thick and 40 mm wide under a 180-ton BATTENFELD press at a temperature of 270 ° C., a mold temperature of 80 ° C. and an injection pressure of 80 kg / cm ² . The injection time is 1.5 seconds. The result of the test is determined by the mold length filled correctly by the composition.

Claims (10)

1. Polyamide comprising macromolecular chains corresponding to the following formulae:

   

   

   in which:

   - Y is the

   

   radical when X and Z represent the

   

   radical,

   - Y is the

   

   radical when X and Z represent the

   

   radical

   - A is a covalent bond or an aliphatic hydrocarbon radical which can comprise heteroatoms and which comprises from 1 to 20 carbon atoms,

   - R₂ is a branched or unbranched aromatic or aliphatic hydrocarbon radical comprising from 2 to 20 carbon atoms,

   - R₃ represents:

   - hydrogen when Z represents the

   

   radical,

   - hydroxyl when Z represents the

   

   radical, or

   - a hydrocarbon radical comprising a

   

   or

   

   group,

   - R₄ represents:

   - hydrogen when Y represents the

   

   radical,

   - hydroxyl when Y represents the

   

   radical, or

   - a hydrocarbon radical comprising a

   

   or

   

   group,

   - R₅ represents hydrogen or a hydrocarbon radical comprising from 1 to 6 carbon atoms,

   - R₁ is a linear or cyclic, aromatic or aliphatic hydrocarbon radical which comprises at least 2 carbon atoms and which can comprise heteroatoms,

   - m represents an integer between 3 and 8,

   - n represents a number between 100 and 200,

   - p represents a number between 100 and 200,

   characterized in that the ratio by mass of the weight of polymer chains of formula I to the total weight of polymer chains of formulae I and II is between 0.6 and 0.9.
2. Polyamide according to Claim 1, characterized in that R₂ is a pentamethylene radical.
3. Polyamide according to either of the preceding claims, characterized in that R₁ represents the cyclohexanonetetrayl radical, the propane-1,1,1-triyl radical, the propane-1,2,3-triyl radical or the

   

   radical.
4. Polyamide according to one of Claims 1 to 3, characterized in that A represents a methylene, polymethylene or polyoxyalkylene radical.
5. Polyamide according to one of Claims 1 to 4, characterized in that m is equal to 3 or 4.
6. Process for the manufacture of a polyamide according to one of Claims 1 to 5, characterized in that it consists in polycondensing an amino acid of formula:
   
           HOOC-R₂-NH₂     (III)
   
   and/or a lactam of formula:

   

   in the presence of a polyfunctional compound of formula (V) :

   - R₁-[-A-X-H]_m, when X represents the

   

   radical, and

   - R₁-[-A-X-OH]_m, when X represents the

   

   radical,

   in which A, R₁, R₂, X and m have the meanings indicated above, in the presence of a polycondensation initiating compound.
7. Process according to Claim 6, characterized in that the polycondensation initiator is water, an inorganic or carboxylic acid or a primary amine.
8. Process according to Claim 6 or 7, characterized in that the polyfunctional compound of formula (V) is chosen from the group comprising the compound 2,2,6,6-tetra(β-carboxyethyl)cyclohexanone, the compound diaminopropane-N,N,N',N'-tetraacetic acid, and the triamines sold under the name JEFFAMINES T® and obtained by reaction of propylene oxide with trimethylolpropane or glycerol and amination of the hydroxyl ends.
9. Process according to one of Claims 6 to 8, characterized in that the concentration by weight in the reaction mass of polycondensation initiator is between 0.5% and 5%.
10. Process according to one of Claims 6 to 9, characterized in that the molar proportion of the polyfunctional compound with respect to the sum of the polyfunctional compound and of the amino acid and/or lactam is between 0.3 and 0.5%